According to the article the bots are only doing random picks from a pool of 18 heroes for now. I imagine pick/ban will come with later iterations.
It's not that clear. They call it "Random Draft", but this picking mode in Dota 2 doesn't mean "doing random picks". "Doing random picks" is the "All Random" mode.
They will apparently be playing Random Draft mode, which normally means that it works similarly to All Pick, except for the fact that the players pick from a pool of 50 random heroes. How this will work with the 18-hero pool is something I don't know.